UUID Version 3

About UUID Version 3

UUID V3 Overview:

UUID3 is part of the UUID family and is specifically designed for deterministic generation. Its uniqueness is derived from hashing a namespace identifier and a name using the MD5 algorithm. The result is a 128-bit identifier that remains consistent for a given namespace and name combination.

Structure of UUID3:

A UUID3 is structured similarly to other UUID versions, featuring a 32-character hexadecimal representation. The key components include the UUID version (3), the namespace identifier, and the hashed value of the namespace identifier and name.

Namespace Identifiers:

As per the RFC 4122 :

• DNS Namespace:

  • UUID: 6ba7b810-9dad-11d1-80b4-00c04fd430c8

• URL Namespace:

  • UUID: 6ba7b811-9dad-11d1-80b4-00c04fd430c8

• OID Namespace:

  • UUID: 6ba7b812-9dad-11d1-80b4-00c04fd430c8

• X.500 Distinguished Names Namespace:

  • UUID: 6ba7b814-9dad-11d1-80b4-00c04fd430c8

Examples of UUID3:

Using the URL namespace, below are the UUIDs for different URLs

• https://www.stackoverflow.com : cb6b2233-c56e-3c2a-af2d-d7bb6472379a
• https://google.com : 34be571d-7180-3bcf-bbda-20cffbfae9ed

In this example, the namespace identifier and name were used to generate a deterministic UUID3.

Deterministic Hashing:

The core principle behind UUID3 lies in deterministic hashing. Unlike random-based UUIDs, UUID3 relies on a predictable algorithm (MD5) to generate the identifier. This means that for the same namespace identifier and name combination, the resulting UUID3 will always be the same. Deterministic hashing is valuable in scenarios where reproducibility and consistency are paramount.

Applications of UUID3:

UUID3 finds its applications in various contexts, particularly where deterministically generated, reproducible identifiers are necessary. Examples include scenarios where uniqueness is required for specific names within a defined namespace, such as generating unique identifiers for objects or resources based on their names.

Implementing UUID3:

To implement UUID3, developers can leverage programming languages and libraries that support the generation of UUIDs. It involves specifying the namespace identifier and name and using the MD5 hashing algorithm to create the UUID3. While UUID3 may not be as widely used as other versions, it has its niche where deterministic uniqueness is a critical requirement.